Another milestone in Chromosome Pathology Section is the introduction of the Methylation Array analysis as a novel clinical test (under CLIA certification, CAP accreditation) offered to the CCR and outside clinical community. Currently, this is one of the two diagnostic laboratories in US offering Methylation Array analysis in clinical setting. This is an NCI LP initiative, NCI COMPASS Program, under a new LP leadership. Establishing a comprehensive tumor molecular profile would assist ultimately in diagnostic precision and overall would impact the treatment decision and the outcome of the therapy. Methylation array analysis based on Illumina platform has been introduced to become an important addition to existing molecular diagnostic menu. Starting from October 2018 the group moved forward with the Methylation array clinical validation to offer it as a clinical test, initially, for the Central Nervous System (CNS) tumor analysis in March 2019. Soon, the other cancer types will be added to the Methylation Classifier list. Overall, 85 cases were included in validation. 188 clinical cases have been officially reported, and 83 cases were studied as part of clinical research projects. This work is being performed in collaboration with the Neuro-Oncology Branch, NCI